Re: Firewall with no engine

Jay Scheevel

Thanks Jon,


I had seen this video previously and it has some good advice, so I watched it again. I have two of Mike Busch’s books and have absorbed them, as well as most of John Schwanner’s Engine maintenance material. All very good stuff. It is all focused on LyCon engines as would be expected given the number of those operating and the tendency of homebuilders with odd engines to do their own maintenance.


I have more or less the same philosophy as you have with respect to treating my Jabiru as an alternative engine. I put in 1/4 turn fasteners on the cowl at the start, and my engine can be removed by unplugging everything at the firewall and never having to put a wrench on the backside of the firewall.


I consider my plane and engine combination to be a prototype, so I treat it that way. So far, my ad hoc engineering has been reliable, but the best way to keep it that way is to look things over very carefully. I have almost 200 hours on it so far, so I am getting close to entering the “goldilocks zone” very soon. I will probably taper off on the invasive inspections as time goes by, but I like being my own worst critic and that makes me err on the tedious side of inspections.


Thanks for your carefully thought out note and for sharing your experience over the years.





From: <> On Behalf Of Jon Finley
Sent: Wednesday, October 6, 2021 8:09 AM
Subject: Re: [Q-List] Firewall with no engine


Mike Busch has put a really good video/article together regarding 'maintenance minimalism' or 'maintenance-induced failures'. I think it's worth watching. Here:

I've also built/flown behind several alternative/auto engines and felt that it was mandatory to keep a VERY close eye on them. I wore out MANY cowling nutplates/screws pulling that thing off after nearly every flight to check things (before I could afford quarter-turn fasteners).  In this scenario many items under the cowling (custom brackets, mounts, etc.) have zero 'fleet hours' on them - that's what the builder is accruing.  For me, this 'problem' was amplified since I was a hack.  At one point, I believed that if an item survived 20-30 hours it was going to last forever. Then I learned about how metal fatigues and started thinking I needed to watch things CLOSER the more hours I put on them.  Doh!!! :-)

So, IMO, there are some different scenarios that don't fit into the same mold. No doubt that finding a balance is the trick.

Now that I fly a Lycoming, I feel a bit guilty that I only remove the cowling every 50-75 hours (for an oil change). :-)

Jon Finley
Somewhere in the Southwest flying an RV-4

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